Heat-resistant structural element and the like



QLHH-bi'i m; m lziaall UM Dec. 20, 1966 w, o zw 3,292,326

T HEAT-RESISTANT STRUCTURAL ELEMENT AND THE LIKE CROSS REERENCE FiledMay 28, 1963 United States Patent HEAT-RESISTANT STRUCTURAL ELEMENT ANDTHE LIKE Wilhelm Holzwarth, Frankfurt am Main, Germany, assignor toOlaculith Patentverwertungs A.G. Filed May 28, 1963, Ser. No. 284,780

Claims priority, application Germany, May 29, 1962,

Claims. (Cl. 52-232) The present invention relates to a heat-resistantstructural element or the like and, more particularly, the presentinvention is concerned with a structural or building element havingfire-resistant and heat-insulating properties and, according to apreferred embodiment of the present invention, also havingradiation-blocking propertim, which element may be in the shape of aplate, a box, a shell for covering another body or building element andthe like. It is frequently desirable and sometimes required by buildingordinances and the like to protect building elements against fire andheat. For instance, the steel skeleton of buildings usually must becovered with fire-resistant material. More recently it has also beenrequired in many cases that structures of reinforced concrete,particularly with prestressed reinforcements, as well as othertemperature sensitive structures are shielded or covered withfire-resistant material.

conventionally, protection against fire was accomplished by applying toan intermediate wall or, for instance, to a false ceiling of wire mesh amortar or plaster layer which layer was required to have a thickness ofat least 3 cm. and had to be formed of highly insulating fireresistantmortar or plaster. Considerable labor is involved in applying suchplaster layer of the required thickness and, furthermore, since theplaster layer has to be applied in wet condition, temporarily thesupporting structure has to carry a weight which is considerably greaterthan that of the dried plaster layer. In order to be able to carry thewet weight of the plaster layer, the dimensions of the supportingstructure frequently have to be increased considerably beyond thedimensions which would be required for carrying only the dry plasterlayer. Furthermore, considerable quantities of moisture are introducedin the form of wet plaster or mortar and the drying of the protectivelayer requires time and possibly heating or ventilating arrangements,all of which increases the costs of providing the fire and heatprotection.

It has been tried to overcome the above discussed difi'iculties anddisadvantages by forming a protective structure of prefabricated plates.However, the plates suggested for this purpose up to now do not seem to-fulfill all requirements with respect to fire resistance and heatinsulation. Upon prolonged testing, most of these prefabricated platescould not withstand the required high temperatures, or, in fire tests,the plates were damaged by the 'water used for extinguishing the fire.It was also not possible in these cases to sufficiently prevent orreduce the passage of heat through the joints between adjacent plates.Thus, there are, for instance, no prefabricated plates available which,with respect to fire resistance will comply with the German standardsDIN 4102 and which, in accordance therewith, could be labeled asfire-resistant structural or building elements.

It is therefore an object of the present invention to overcome theabove-discussed difficulties and disadvantages in the protection ofbuilding elements and the like against fire and heat.

It is a further object of the present invention to provide a shaped,prefabricated building element and a structure consisting of a pluralityof such building elements joined to each other, which structure, forinstance, may be in the shape of plates, boxes, or shells of anyconfiguration 3,292,326 Patented Dec. 20, 1966 suitable for protectingthe structure covered thereby, which protective building element orstructure will possess high fire-resistant and heat-insulatingproperties and can be produced and assembled in a simple and mechanicalmanner.

It is yet another object of the present invention to provide suchprotective fire and heat-resistant element and structure which, inaddition thereto, will also be capable of absorbing and thereby blockingthe passage of radiation.

Other objects and advantages of the present invention will becomeapparent from a further reading-of the description and of the appendedclaims.

With the above and other objects in view, the present invention includesa composite structure element having fire-resistant and heat-insulatingproperties, comprising, in combination, a plurality of shaped solidbodies consisting of a mixture of (1) a substance selected from thegroup consisting of expanded perlite and vermiculite, (2') clay and (3)a substance selected from the group consisting of cement and gypsum, theshaped solid bodies being arranged adjacent to each other with adjacentedge faces of adjacent bodies spaced from each other but a shortdistance defining a narrow open space therebetween, and a solid binderconsisting essentially of an intimate mixture of perlite, glass powder,water glass and clay substantially filing the narrow open space therebyfirmly adhering the shaped solid bodies to each other.

The term cement as used in the following specification and claims isintended to include also gypsum.

According to a preferred embodiment of the present invention, the samecomprises in a composite structural element having fire-resistant andheat-insulating properties, a plurality of plates consisting of aboutsix parts by volume of perlite, about two parts by volume of plaster ofParis and about one part by volume of bentonite, the plates havingreinforcing members of expanded metal incorporated therein and theplates being arranged adjacent to each other in edge-to-ed-gerelationship, adjacent edges of adjacent plates having along the lengththereof spaced projections and recesses, the projections of one of theadjacent edges registering with the recesses of the other of theadjacent edges and being located within and spaced from the .same so asto define a narrow open space between the adjacent edges; a solid binderconsisting essentially of about two parts by volume of water glass,about two and one half parts by volume of glass powder, about two andone half parts by volume of perlite, and about one half part by volumeof benton-ite filling the narrow open space thereby forming a compositeplate having opposite faces, and a layer consisting of about fifty partsby volume of lead powder, about thirty parts by volume of quartz sand,about ten parts by volume of cement and about ten parts by volume ofbentonite, the layer having radiation-blocking properties, substantiallycoverin g one of the opposite faces.

Thus, according to the present invention, it is possible by assemblingprefabricated bodies of the desired shape to provide fire resistant andheat insulating coverings or casings which will have the desired fireresistance and heat insulating properties throughout, including thejoints between the individual plates or the like and also including theportions thereof at which the protective structure is supported orsuspended.

According to the present invention an insulating material of the abovedescribed composition is combined with certain structural features ofthe edges of the insulating bodies, plates or the like, which arelocated adjacent to and facing each other; and the joints betweenadjacent insulating bodies are filled with a binder material of theabove described composition.

Preferably, the insulating plates or the like are formed of an intimatemixture of about six parts by volume of perlite, about one part byvolume cement and one part by volume clay. Throughout the presentspecification and claims wherever proportions are given in parts byvolume, it is to be understood that such proportions may deviateupwardly and downwardly by up to about Thus, for instance, six parts byvolume of perlite are meant to denote between 5.4 and 6.6 parts byvolume thereof.

Perlite is a well known inorganic incombustible material containingclosed micropores and is produced of volcanic mineral in an expansionprocess requiring heating of the mineral to more than 1000 C. By thisexpansion process, the volume of the mineral material is increased tobetween about and times its orginal volume. Perlite is resistant tomoisture, non-hygroscopic and possesses a relatively high pressureresistance. The heat conductivity of perlite (lamba) equals between0.034 and 0.040 kcaL/mh. C. Preferably, a commercially available perlitehaving particle sizes of up to 4 mm. and a specific gravity of between50 and 70 kg./m. is used. The cement preferably will be of a quicklybinding type and the preferred clay is natural bentonite correspondingsubstantially to the formula:

It is also possible to replace the cement of the plate forming mixturewith gypsum or preferably with plaster of Paris. In this case, thepreferred composition of the mixture will be six parts by volume ofperlite, two parts by volume of gypsum and one part by volume of clay.

Insulating bodies according to the present invention which will beexposed to atmospheric conditions or placed in moist locations arepreferably made of a cement-containing mixture.

In all of the above described mixtures, perlite may be replaced with anequal proportion of vermiculite.

Preferably, the adjacent edges of adjacent insulating plates or the likeaccording to the present invention will dove-tail or will be formed withregistering projections and recesses whereby a depth of the recess ofbetween about 2 and 2.5 cm. will suffice. However, the adjacent edgesmay also be formed with other types of overlapping or intermeshingfaces.

The joints formed between adjacent edges are then filled with a bindermaterial which originally contains an organic binder, perlite, glasspowder and clay, the latter preferably in the form of bentonite.

Preferably, the binder material will be of the following composition:two parts by volume of a 50% nonre-emulsifiable dispersion ofpolyvinylpropionate, for instance of the type known as Propiofan 5D, 6Dmade by BASF, 2 parts by volume of water glass, 2.5 parts by volume ofperlite, 2.5 parts glass powder and 0.5 part bentonite.

The 50% polyvinylpropionate dispersion commercially available from theBadische Anilin- & Soda-Fabrik AG under the trade name Propiofan can bediluted with water to any desired degree but will give upon drying awater insoluble film which cannot be re-emulsified. The size of thesuspended particles is between 0.3 and 2 microns.

The organic binder material of the above mixture which initiallyprovides the adhesive power will be destroyed upon exposure tosufiiciently high temperatures and the remaining inorganic constituentsof the mixtures will then form a firm fire resistant and heat insulatingbonding material which may safely be exposed to temperatures of up toand even in excess of 1000 C.

To increase the mechanical strength of the prefabricated insulatingplates or bodies, particularly when the same are of relatively largedimensions, it is preferred to reinforce the same by embedding in theplate forming material or the like, during molding of the same, areinforcing structure consisting, for instance, of a mesh of structuralsteel. Preferably expanded metal formed with flat ribs is used for thispurpose and it has been found that expanded metal which has a maximumcross sectional dimension of about 5 mm. is particularly suitable.

For most purposes a plate thickness of between about 30 and 38 mm. willsufiice, however, it is of course within the scope of the presentinvention to provide plates or other shaped fire resistant and heatinsulating bodies of greater or also of smaller cross sectionaldimensions.

According to a preferred embodiment of the resent invention, the heatinsulating and fire resistant structure will also absorb and thus blockradiation such as radioactive rays. This is achieved by applying to oneface of the insulating body a lead-containing layer, having a thicknessof for instance 20 mm. Such radiation blocking layer may be formed of amixture of 50 parts by volume lead powder having a particle size of upto 1 mm., 30 parts by volume quartz sand, 10 parts by volume cement and10 parts by volume clay, preferably bentonite. Here again it should beunderstood that the indications of volumetric proportions are meant toinclude a tolerance of 10% in either direction.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention, itself, however, both as to its construction and its methodof operation, together with additional objects and advantages thereof,will be best understood from the following description of specificembodiments when read in connection with the accompanying drawing, inwhich the figure is a fragmentary elevational view, partially in crosssection of a ceiling structure protected against heat, fire andradiation in accordance with the present invention.

As shown in the drawing, the ceiling structure comprises I-bearns 1supporting a steel reinforced concrete plate 2. The protective structureaccording to the present invention consists of a false ceiling which issuspended from I-beams 1. Elongated bars 4 of T-shaped cross section aresuspended by suitable hook-shaped elements and wires from elongated bars3 of suitable cross section which rest on the lower flanges of the beams1, portions of the bars 4 also being connected to the lower flanges ofthe beams 1. The lower portions of the bars 4 are perforated and havefastened thereto, by means of countersunk screws, the insulating plateswhich have a thickness of approximately 30 mm. and which are reinforcedwith expanded, ribbed steel 9. The insulating plates 5 are provided withmating projections 6 which complement and overlap each other at the sideedges of the plates 5. The gaps between the overlapping portions 6 arefilled and sealed with the binder material 7 described further above.The space between the lower side of the beams 1 and the upper side ofthe insulating plates 5 may be approximately 65 mm.

If protection against radiation is desired, a layer of radiationblocking material 8 may be applied to the lower face of the falseceiling formed by plates 5.

The above described ceiling structure was installed in a test building,the false ceiling extending horizontally and so that the distancebetween parallel I-beams 1 amounted to 4 meters. A fire test was thencarried out in accordance with German standards DIN 4102. Within 10minutes, the temperature within the test building reached 650 C., after30 minutes 880 C., after 60 minutes 1000 C. and after minutes about 1025C. Thereafter, the fire was extinguished within three minutes byapplying a stream of water at a gauge pressure of two atmospheres from adistance of 3 meters.

It was found that 90 minutes after start of the test, at which time thetemperature within the test building had reached 1012 C., the averagetemperature at the reinforced concrete plates 2 amounted to only 38 C.The temperature at the lower flange of I-beams 1 did not rise above 88C. Surprisingly, it was also found that the portion of the upper face ofthe false ceiling formed of plates 5 did not exceed 57 C. even at thebinderfilled joints thereof. During the subsequent extinguishing of thefire by applying water under pressure as described above, the falseceiling resisted the stream of water without breaking.

It was thus found that the protective ceiling structure according to thepresent invention could resist for one and one-half hours exposure tofire and subsequent contact with water under pressure used forextinguishing the fire and that during the entire test the structure ofthe false ceiling remained essentially unaffected.

The mechanical strength of the entire ceiling structure including itsload carrying capacity was not diminished and the fire could notpenetrate through the false ceiling. Thus, the structure according tothe present invention and as illustrated herein complied with therequirements of the German standards applicable for fire resistantstructural elements.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofprotective structural elements differing from the types described above.

While the invention has been illustrated and described as embodied in afire and heat resistant false ceiling, it is not intended to be limitedto the details shown, since various modifications and structural changesmay be made without departing in anyway from the spirit of the presentinvention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofshaped solid bodies consisting of a mixture of (1) a substance selectedfrom the group consisting of expanded perlite and vermiculite, (2) clayand (3) cement, said shaped solid bodies being arranged adjacent to eachother with adjacent edge faces of adjacent bodies spaced from each otherbut a short distance defining a narrow open space therebetween; and asolid binder consisting essentially of an intimate mixture of perlite,glass powder, water glass and clay substantially filling said narrowopen space thereby firmly adhering said shaped solid bodies to eachother.

2. In a building structure, a first Wall; a second wall adjacent saidfirst wall, said second wall comprising a plurality of plates consistingof a mixture of (1) a substance selected from the group consisting ofexpanded perlite and vermiculite, (2) bentonite and (3) cement, saidplates being arranged adjacent to each other with adjacent edge faces ofadjacent plates spaced from each other but a short distance defining anarrow open space therebetween, and a solid binder consisting of anintimate mixture of an organic binder material, perlite, glass pow der,water glass and clay substantially filling said narrow open spacesthereby firmly adhering said plates to each other; and attaching meansfor attaching said second wall to said first wall, whereby said firstWall will be protected against fire and heat by the interposition ofsaid second wall between said first Wall and a source of fire and heat.

3. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofplates consisting of a mixture of (1) a substance selected from thegroup consisting of expanded perlite and vermiculite, (2) bentonite and(3) cement, said plates being arranged adjacent to each other inedge-to-edge relationship, adjacent edges of adjacent plates havingalong the length thereof spaced projections and recesses, theprojections of one of said adjacent edges registering with the recessesof the other of said adjacent edges and being located within and spacedfrom the same so as to define a narrow open space between said adjacentedges; and a solid binder consisting essentially of an intimate mixtureof an organic binder material, perlite, glass powder, water glass andclay substantially filling said narrow open space thereby firmlyadhering said plates to each other.

4. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofshaped solid bodies consisting of a mixture of (1) about six parts byvolume of a substance selected from the group consisting of expandedperlite and vermiculite, (2) about one part by volume of clay and 3)about one part by volume of cement, said shaped solid bodies beingarranged adjacent to each other with adjacent edge faces of adjacentbodies spaced from each other but a short distance defining a narrowopen space therebetween; and a solid binder consisting essentially of anintimate mixture of perlite, glass powder, water glass and claysubstantially filling said narrow open space thereby firmly adheringsaid shaped solid bodies to each other. 1

5. A composite structural element having fire-resistan andheat-insulating properties, comprosing, in combination, a plurality ofshaped solid bodies consisting of a mixture of about six parts by volumeof perlite about two parts by volume of plaster of Paris and about onepart by volume of bentonite, said shaped solid bodies being arrangedadjacent to each other with adjacent edge faces of adjacent bodiesspaced from each other but a short distance defining a narrow open spacetherebetween; and a solid binder consisting essentially of an intimatemixture of perlite, glass powder, water glass and clay substantiallyfilling said narrow open space thereby firmly adhering said shaped solidbodies to each other.

6. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofplates consisting of a mixture of (l) a substance selected from thegroup consisting of expanded perlite and vermiculite, (2) clay and (3)cement, said plates having reinforcing members of expanded metalincorporated therein and said plates being arranged adjacent to eachother with adjacent edge faces of adjacent bodies spaced from each otherbut a short distance defining a narrow open space therebetween; and asolid binder consisting essentially of an intimate mixture of perlite,glass powder, water glass and clay substantially filling said narrowopen space thereby firmly adhering said plates to each other.

7. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofshaped solid bodies consisting of a mixture of (1) a substance selectedfrom the group consisting of expanded perlite and vermiculite, (2) clayand (3) cement, said shaped solid bodies being arranged adjacent to eachother with adjacent edge faces of adjacent 'bodies spaced from eachother but a short distance defining a narrow open space therebetween;and a solid binder consisting of about two parts by volume of a 50%dispersion of polyvinyl propionate, about two parts by volume of waterglass, about two and one half parts by volume of glass powder, about twoand one half parts by volume of perlite and about one half part byvolume of bentonite filling said narrow open space thereby firmlyadhering said shaped solid bodies to each other.

8. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofplates consisting of a mixture of 1) a substance selected from the groupconsisting of expanded perlite and vermiculite, (2) clay and (3) cement,said plates being arranged adjacent to each other with adjacent edgefaces of adjacent plates spaced from each other but a short distancedefining a narrow open space therebetween; a solid binder consistingessentially of an intimate mixture of perlite, glass powder, water glassand clay substantially filling said narrow open space thereby andheat-insulating properties, comprising, in combination, a plurality ofplates consisting of a mixture of (1) a substance selected from thegroup consisting of expanded perlite and vermiculite, (2) clay and (3)cement, said plates being arranged adjacent to each other with adjacentedge faces of adjacent plates spaced from each other but a shortdistance defining a narrow open space therebetween; a solid binderconsisting essentially of an intimate mixture of perlite, glass powder,water glass and clay substantially filling said narrow open spacethereby forming a composite plate having opposite faces; and a layerconsisting of about fifty parts by volume of lead powder, about thirtyparts by volume of qpgrtz 82nd,.

about ten parts by volume of cement and about ten parts by volume ofbentonite, said layer having radiation-blocking properties,substantially covering one of said opposite faces.

10. A composite structural element having fire-resistant andheat-insulating properties, comprising, in combination, a plurality ofplates consisting of about six parts by volume of perlite, about twoparts by volume of plaster 39 of Paris and about one part by volume ofbentonite, said plates having reinforcing members of expanded metalincorporated therein and said plates being arranged adjacent to eachother in edge-to-edge relationship, adjacent edges of adjacent plateshaving along the length thereof spaced projections and recesses, theprojections of one of said adjacent edges registering with the recessesof the other of said adjacent edges and being located within and spacedfrom the same so as to define a narrow open space between said adjacentedges; a solid binder consisting essentially of about two parts byvolume of water glass, about two and one half parts by volume of glasspowder, about two and one half parts by volume of perlite, and about onehalf part by volume of bentonite filling said narrow open space therebyforming a composite plate having opposite faces; and a layer consistingof about fifty parts by volume of lead powder, about thirty parts byvolume of quartz sand, about ten parts by volume of cement and about tenparts by volume of bentonite, said layer having radiation-blockingproperties, substantially covering one of said opposite faces.

References Cited by the Examiner UNITED STATES PATENTS 2,037,294 4/1936Williamson 52-612 2,213,603 9/1940 Young 52-612 2,466,106 4/1949 Hoge52483 2,703,289 3/1955 Wilson 52-612 3,015,626 1/1962 Kingsbury 252- 623,095,347 6/1963 Becker 106122 X FRANK L. ABBOTT, Primary Examiner.

I. E. MURTAGH, Assistant Examiner.

1. A COMPOSITE STRUCTURAL ELEMENT HAVING FIRE-RESISTANT ANDHEAT-INSULATING PROPERTIES, COMPRISING, IN COMBINATION, A PLURALITY OFSHAPED SOLID BODIES CONSISTING OF A MIXTURE OF (1) A SUBSTANCE SELECTEDFROM THE GROUP CONSISTING OF EXPANDED PERLITE AND VERMICULITE, (2) CLAYAND (3) CEMENT, SAID SHAPED SOLID BODIES BEING ARRANGED ADJACENT TO EACHOTHER WITH ADJACENT EDGE FACES OF ADJACENT BODIES SPACED FROM EACH OTHERBUT A SHORT DISTANCE DEFINING A NARROW OPEN SPACE THEREBETWEEN; AND ASOLID BINDER CONSISTING ESSENTIALLY OF AN INTIMATE MIXTURE OF PERLITE,GLASS POWDER, WATER GLASS AND CLAY SUBSTANTIALLY FILLING SAID NARROWOPEN SPACE WHEREBY FIRMLY ADHERING SAID SHAPED SOLID BODIES TO EACHOTHER.